Grinding machine



Sept. 10, 1957 Filed Aug. 16, 1956 H. A. $ILVEN GRINDING MACHINE 5Sheets-Sheet l INVENTOR HERBERT A.5/L VEN A TTOENEY Sept. 10, 1957 H. A.SILVEN GRINDING momma 5 Sheets Sheet 5 Filed Aug. 16, 1956 INVENTORHERBERT A. 5/1. VEN

ATTORNEY Sept. 10, 1957 H. A. SILVEN GRINDING MACHINE 5 Sheets-Sheet 4E1166. Aug. 16, 1956 INVENTOR HERBERT A.5ILVEN LDBQJam.

ATTO ENE Y Sept. 10, 1957 v H. A. SILVEN 2,805,524

' GRINDING MACHINE Filed Aug. 16, 1956 Sheets-Sheet 5 WORK M A TTOENEYUnited States Patent GRnsmNG MACHINE Herbert A. Silven, West Boylston,Mass, assignor to Norton Company, Worcester, Mass, a corporation ofMassachusetts Application August 16, 1956, Serial No. 664,378

11 Claims. (Cl. 51-103) The invention relates to grinding machines, andmore particularly to a centerless-type grinding machine.

One object of the invention is to provide a simple and thoroughlypractical automatically operated centerless grinding machine. Anotherobject is to provide a centerless grinding machine in which successivework pieces are supported by a pair of spaced work shoes and driven by arotatable driving element. Another object is to provide a pair of worksupporting shoes, one of which is fixed and the other is movable towardthe fixed shoe in an arcuate path to facilitate rounding-up the workpiece being ground. Another object is to provide a shoe moving mechanismfor imparting a control led arcuate movement to the movable worksupporting shoe by and in timed relation with the infeeding movement ofthe grinding wheel.

A further object is to provide an automatically operated work loadingmechanism for conveying successive work pieces into operative grindingposition. Another object is to provide an automatically indexed workloading turret for conveying successive work pieces to and from agrinding position. Another object is to provide means for moving thework supporting shoes to and from an operative position to facilitateactuation of the work loading turret. Other objects will be in partobvious or in part pointed out hereinafter.

In the accompanying drawings in which is shown one of various possibleembodiments of the mechanical features of this invention;

Figure 1 is a front elevation of the improved grinding machine;

Figure 2 is a fragmentary vertical sectional view on an enlarged scale,through the grinding machine showing the wheel feeding mechanism;

Figure 3 is a fragmentary horizontal section view, on an enlarged scalethrough the work head;

Figure 4 is a fiagmentary left hand end elevation, on an enlarged scale,taken approximately on the line 44 of Fig. 3, showing the arrangement ofthe Work supporting shoes;

Figure 5 is a fragmentary sectional view on an enlarged scale takenapproximately on the line 55 of Fig. 3 through a portion of the Workloading turret actuating mechanism;

Figure 6 is a right hand end elevation of the work turret indexingmechanism, as shown in Fig. 3;

Figure 7 is a vertical sectional view, through the work loadingmechanism including the work chute and loading turret;

Figure 8 is a fragmentary sectional view, taken approximately on theline 88 of Fig. 7; and

Figure 9 is a combined hydraulic and electric diagram of the actuatingmechanisms and the controls therefor.

A grinding machine has been illustrated in the drawings comprising abase 10 which supports a longitudinally movable work table 11 on theusual fiat way 12 and the V-way 13 (Fig. 2) formed on the upper surfaceof the base it). The table 11 serves as a support for swivel table 14which carries a headstock unit 15 and a, footstock unit 16.

The Work head 15 is provided with a suitable driving mechanism includingan electric motor 20 mounted on the upper surface of the head 15. Themotor 20 is connected by a multiple V-belt drive (not shown) containedwithin a belt guard 21 to drive a rotatable shaft 22. The shaft 22 isoperatively connected to impart a rotary motion to a work drivingspindle 23. The work spindle 23 serves as a support for africtional-type work driver, such as a permanent magnet chuck 24 whichis arranged in a manner hereinafter described to impart a rotary motionto the work piece to be ground.

The base It) also supports a transversely movable wheel slide 30 on theconventional fiat way and V-way (not shown). The wheel slide 30 isprovided with a rotatable wheel spindle 31 which supports a grindingwheel 32 at its left hand end (Fig. 1). A grinding wheel drivingmechanism is provided comprising an electric motor 33 mounted on theupper surface of the wheel slide 30. The motor 33 is provided with amotor shaft 22 which supports a multiple V-groove pulley 35. The pulley35 is connected by multiple V-belts 36 with a multiple V-groove pulley37 mounted on the right hand end of the wheel spindle 31 (Fig. 1).

A feeding mechanism is provided for imparting a transversely feedingmovement to the wheel slide 30. A screw 44) (Fig. 2) is provided fortransmitting a traverse feeding movement to the wheel slide 36. The lefthand end of the feed screw 4% is slidably keyed within a rotatablesleeve 41 which is journaled in anti-friction bearings 42 which arefixedly supported relative to the base 10. The right hand end of thefeed screw is supported by anti-friction bearings 43 which are carriedby a slidably mounted sleeve 44. The sleeve 44- is arranged to slidetransversely within a cylindrical aperture 45 formed in fixed relationto the base 10. The wheel slide 30 is provided with a depending bracket46 which contains a rotatable feed nut (not shown) which meshes with orengages the threads on the feed screw 40. A rotatable shaft 47 isslidably keyed Within the left hand end of the sleeve 41. The left handend of the shaft 47 is journaled in anti-friction bearings 48. A gear 49mounted on the left hand end of the shaft 47 meshed with a gear 54). Thegear Stl is operatively connected to be rotated by a manually operablefeed wheel 51 which is supported on the front of the machine base 10.The feed wheel 51 is provided with the well-known micrometer feederadjusting mechanism 52. A feed pawl 53 is pivotally supported by a stud54 on-the front of the machine base. An ad justable stop abutment 52a(Fig. 9) carried by the feed wheel 51 is arranged to engage the end faceof the pawl 53 to facilitate positively stopping the end feedingmovement of the wheel slide 30.

A hydraulically operated mechanism is provided for imparting a rapidpositioning movement to the wheel slide 30 to facilitate rapidly movingof the grinding wheel 32 into an engagement with the work piece beingground and to rapidly withdraw the grinding wheel to an in: operativelypositioning after a grinding operation has been completed. Thismechanism comprises a cylinder '55 which is arranged in axial alignmentwith the feed screw 40 and the sleeve 44. The cylinder 55 contains aslidably mounted piston 56 mounted on the right hand end of a piston rod57 (Fig. 2 and 9). The left hand end of the piston rod 57 is operativelyconnected to move the sleeve 44 so as to transmit a correspondingmovement to the feed screw 40, the wheel slide 30, and the grindingwheel' A feed control valve 60 is provided for controlling the admissionto and exhaust of fluid from the cylinder 55. The control valve 60 is apiston type valvecompris-" ing a slidable valve member 61 having .aplurality of spaced valve pistons formed integrally therewith to formspaced valve chambers 62, 63, 64 and 65. The slidably mounted valvernember is provided with acentral b15251 sage 66 which interconnects thevalve chamber 63 :with the-valve chamber 65. A compression spring 67serves normally to hold the valve member 61 in a right hand, endposition. A solenoid S1 is provided which when energised serves to shiftthe valve member 61 toward. the left so as to reverse the flow of fluidto the cylinder 55. A fluid pressure system is provided for supplyingfluid under' pressure to the various actuatingmechanisms of themachine.- This system comprises a motor driven fluid pump 7 which drawsfluid through a pipe 71 from 'a reservoir- 72 and passes fluid underpressure through a pressure pipe '73. A relief valve 74 is connectedwith the pipe 73 to facilitate exhausting excess fluid under pressuredirectly through a pipe 75 into the reservoir 72 thereby maintaining asubstantially constant fluid pressure with thesystem.

v In the position of the valve 60 (Fig. 9) fluid under pressure from thepressure pipe 73 enters the valve chamber 62 and'passes through apassage 78 and through a port 79 into a cylinder chamber 83 formed atthe left hand end of the cylinder 55. Fluid under pressurepassingthrou'gh the passage 78 also passes through a ball check valveSll and a throttle valve 81 into the cylinder chamber 83 to move thepiston'56 toward the right (Fig. 9) into a rearward position therebymoving the wheel slide 30 and the grinding wheel 32 away from engagementwith the work piece being ground. During this movement of the piston 56,fluid within a cylinder chamber 84 exhaus ts through a passage 85 intothe valve chamber '64 and exhaust through a pipe 89 into thefreservoir72. A dash pot piston 86 is provided to facilitate slowing down andcushioning the movement of the piston 56' as it approaches a right handend position. a dash pot exhausts through a throttle valve 87 into thepassage 85. By manipulation of the throttle valve 87, the rateofmovement of the dash pot piston 86 toward the right may be regulatedas desired. A. ball check valve 88 is provided in the passage 85 tofacilitate by passing the throttle valve 87 when fluid under pressure ispassed through the passage 85 to cause movement of the piston 56 towardthe left.. 7

When the solenoid S1 is energized and the valve member 61 is shifted toa left hand end position, fluid under pressure from the pipe 73 entersthe valve chamber 64 and passes through the passage 85 into the cylinderchamber 84 to cause a rapid movement of the piston 56 toward the leftthereby rapidly moving the wheel slide 30 and the grinding wheel 32forward into a grinding position. 7 'At the same time fluid underpressure passing through the passage 85 passes through the ball checkvalve 88'and thethrottle valve 87 to reset the dash pot piston 86, thatis, move it toward the left (Fig. 9). During the rapid work movement ofthe piston 56 toward the left fluid the cylinder chamber 83 may exhaustthrough the port 7 9, through the passage 78 and also exhausts throughthe port 82 and the throttle valve 81 into the passage 78 and into thevalve chamber 62. Fluid exhausting into the valve chamber 62 may thenpass through the exhaust pipe 89 into the reservoir 72; The rapidmovement of the piston 56 toward the left continues until the piston 56closes the port 79 so that thereafter fluid exhausting from the cylinderchamber 83 must pass throughthe port 82 and the throttle valve 81 tofacilitate cushioning the'rapid approach movement of the wheel slide :30and the grinding wheel 32; It will be readily apparent from theforegoing disclosure that manipulation-of the throttle valve 81 servesto regulate the rate of'slow down movement of the piston 56 as itapproaches the left hand end of its stroke;

A fluid. pressure operative'mechanism is provided for controlling theinfeeding movement. of.the grinding wheel.

' through a throttle valve 106 and a ball check valve 107 Fluid within32 during the grinding operation. This mechanism comprises a feedcylinder which contains a slidable piston 96. The piston 96 is providedwith rack teeth 97 which mesh with a gear 98 which is keyed'onto arotatable shaft 99. The shaft 99 is also provided with a gear 100 whichmeshes with the gear 49.

The feed control valve 60 in addition to controlling the admissionto'and exhaust of fluid from the cylinder 55 is operatively connected tocontrol the admission to and exhaust of fluid from the feed cylinder 95.i In the position of the valve 60 (Fig. 9) fluid under pressure enteringthe valve chamber 62 passes through a pipe 105,

through a pipe 108, through a passage 109 into a cylinder chamber 110 tomove'the piston 96 toward the left into the position illustrated in Fig.9. During this movement, fluid within a cylinder chamber 111 at the lefthand end of the cylinder 95 exhausts through a passage 112, through apipe 113, through a ball check valve 114 intothe valve chamber 64 andexhausts through the pipe 89 into the reservoir 72. W

A sequence valve 115 is provided so that when the valve 60 is reversed,a slight delay is obtained before fluid may be passed through thecylinder chamber 111 to. initiate movement of the pistons 96 toward theright.- A compression spring 116 serves normally to hold the sequencevalve 115 in a right hand end position. When the solenoid Slis energizedand the valve member 61 is shifted in a left hand end position, fluidunder pressure entering the valve'chamber 64 passes through a pipe 117The ball check valve 114 is closed so that fluid under pressure passingthrough the pipe 117 must pass through: a pipe 118 into the right handend of the sequencevalve 115. Pressure builds up inthe right hand end ofthe 116 until a chamber'119 moves toward the left a sufiicient distanceso that fluid passing through the pipe 117" may pass through the valvechamber 119 into the pipe 113, through the passage 112 into the cylinderchamber 111 to move the piston 96 toward the right thereby. imparting arotary motion to the feed screw 40 to feed the wheel slide 30 and thegrinding wheel 32 into the work piece being ground. During this movementfluid within the cylinder chamber 110 may exhaust through the passage109, through the pipe 108, through the throttle valve 106 into the valvechamber 62 and exhaust through the pipe 89. By manipulation ofthethrottle valve 106, the rate of movement of the piston 96 toward theright may. be readily controlled to produce the desired rate of infeedof the grinding 'wheel 32. a

It may be desirable at times to feed the grinding wheel 32 by manualactuation of the feed wheel 51 without the bers 122 and 123. The valveis normally held in a.

left hand end position by a'compression spring 124. In

this position, the pipe 108 is connected with the valve: chamber 123which connects with the passage 109. Simi-.

larly the pipe 113 is connected through the valve chamber.

122 with the passage 112. When it is desired to shift the a valve 120 toa by-pass position, a valve 125"may be;

opened to pass fluid under pressure from the pipe'73' through a pipe 126into a chamberl127 formedat the.

left hand end of the valve 120 to move the valve member. 121 toward theright against the compression of the spring 124. In the right handend'position the'valve pistonsi block the ports at the ends of the pipes108 and 113 and the passages 109 and 112 are both connected to the valvechamber 122. 'In this position of the parts the grinding wheel 32*may befed'in either direction by manual actuation of the feed wheel 51without'the necessity of over-'- coming fluid under pressurewithin thesystem. During a' manual actuation of .theifeed .wheel 51 'fl'uid mayreadily 63 by-pass directly from the cylinder chamber 110 into thecylinder chamber 111 and vice versa. The wheel feeding mechanism abovedescribed is substantially identical with that disclosed in the U. S.patent to H. A. Swainey No. 2,693,563 dated May 26, 1953.

A manually operable clutch is provided for disconnecting the hydraulicfeed mechanism when desired. This mechanism, as shown in Fig. 2comprises an external gear 125 which is fixedly mounted to rotate withthe gear 93. The gear 98 is rotatably supported in anti-frictionbeatings. A shaft 127 passes through a central aperature within the gear98 and is provided at right hand end thereof with an internal gear 126which is arranged to mesh with the external gear 125, as shown in Fig.2. A yoked member 128 is provided for axially moving the shaft 127relative to the gear 98. When it is desired to declutch the feed piston96, the yoked member 128 is actuated to move the shaft 27 axially towardthe right so that the internal gear 126 moves out of mesh with theexternal gear 125. When the clutch is disengaged, the feed wheel 51 maybe rotated to impart the rotary feeding movement to the feed screw 40during which movement the feed piston 96 remains stationary.

In order to attain the main object of this invention a centerless typework support is provided for supporting a work piece during a grindingoperation. This work support comprises a work shoe 135 (Fig. 4) which isarranged to support the work piece to be ground at a point below thework axis and adjacent to the periphery of the grinding wheel 32. Asecond work supporting shoe 136 is provided to support the work piece ata point diametrically opposite to the line of contact between grindingwheel 32 and the work piece being ground. This shoe 136 is a preferablymovable shoe which initially engages the work piece being ground at apoint above the horizontal plane passing through the ams of the grindingwheel and the work piece being ground. As the grinding on the work pieceproceeds, the work shoe 136 is moved at a very slow rate in a clockwisedirection as the work piece is reduced in size. The work shoes 135 and136 are supported by the footstock 16 in a manner to be hereinafterdescribed. The footstock 16 is provided with axially movable sleeves 137and 137a which is slidably keyed with an aperture 138 formed in thefootstock housing (Fig. 3). The left hand end of the sleeve 137 isprovided with an integral flange 139 which supports the fixed steadyrest shoe 135. The shoe 135 is arranged so that it may be clamped to theflange 139 by a clamping screw 140. A rotatable spindle 141 is rotatablysupported within an aperture 142 formed in the sleeve 137a. An arm 143is fixedly mounted on the left end of the spindle 141. The arm 143serves as a support for the work rest shoe 136. The arm 143 and the lefthand side face of the gear 155 serve to take up end thrust of the sleeve137 during axial movement of the spindle 141. The arm 143 is providedwith a radially extending T-slot 144. A nut 145 fits within the T-slot144. A clamping screw 146 carried by the work shoe 136 meshes with thenut 145 to facilitate a radial adjustment of the work shoe 136. Asimilar T-slot 147 is provided to facilitate adjustment of the work shoe135 in a radial direction.

A hydraulic operated mechanism is provided for imparting a controlledswinging movement of the work shoe 136. This mechanism comprises acylinder 156 (Figs. 3 and 9) which contains a slidably mounted piston151. The piston 151 is connected to the of a piston rod 152 which isslidably supported in a bearing 153. The piston rod 152 is provided withrack teeth 154 which meshes with a gear 155 formed integral with thespindle 141. A stop screw 156 serves to limit the movement of the piston151 in one direction. A compression spring 157 serves normally to holdthe lower end of the piston rod 152 (Fig. 3) in an engagement with thestop screw 156. When it is desired to impart a control swinging movementto the work shoe 136, fluid is passed through a pipe 158 into a cylinderchamber 159 to move the piston 151 toward the left (Fig. 9) against thecompression of the spring 157. This movement causes the rack teeth 154to impart a clockwise rotary motion to the gear thereby imparting arotary motion to the spindle 141 to move the work shoe 136 in aclockwise direction (Fig. 4).

The swinging movement of the work shoe 136 is preferably in timedrelation with the feeding movement of the piston 96 so that fluid underpressure passes through the chamber 119 into the pipe 113 to initiatethe feeding movement of the piston 196, fluid is also passed through athrottle valve 160, through the pipe 158 into the cylinder chamber 159at a rate controlled by the throttle valve 160. It will be readilyapparent from the foregoing disclosure that by manipulation of thethrottle valve 169 the rate of swinging movement of the work shoe 136may be varied as desired. A ball check valve 161 is provided so thatwhen the feed piston 96 is reset after a grinding operation has beencompleted, that is, moved toward the left, the release compression ofthe spring 157 may exhaust fluid from the cylinder chamber 159 throughthe pipe 158 and through both the throttle valve 160 and the ball checkvalve 161 at a substantially unrestricted rate.

The hydraulically operated mechanism is provided for moving the sleeve137 and the spindle 141 in an axial direction to facilitate a loadingoperation. A cylinder 165 is arranged in an axial alignment with thespindle 141 and the sleeve 137 andcontains a slidably mounted piston166. The piston 166 is connected to the right hand end of a piston rod167. The left hand end of the piston rod 167 is provided with a flangedhead 168 which is fastened to the end of the sleeve 137a. The sleeve1370 is provided screw threaded stud which engage an annular groove 169formed in the spindle 141 (Fig. 3). When fluid under pressure is passedthrough a pipe 17 0 into a cylinder chamher 171, the piston 166 togetherwith the sleeve 137 and spindle 141 are moved toward the left into awork supportin g position for a grinding operation. A control valve isprovided for controlling the admission to and exhaust of fluid from thecylinder 165. The valve 175 is a piston-type valve having a slidablymounted valve member 176 which is provided with a plurality of spacedvalve pistons forming a plurality of spaced valve chambers 177, 178 and179. The valve member 176 is provided with a central passage 180 whichinterconnects the valve chamber 177 with the valve chamber 179. Acompression spring 181 serves normally to hold the valve member 176 in aleft hand end position. A solenoid S2 is provided which when energizedserves to shift the valve member 176 into a right hand end position soas to reverse the flow of fluid under pressure to the cylinder 165. Inthe position of the parts as shown in Fig. 9, fluid under pressure fromthe pipe 73 enters the valve chamber 178 and passes through the pipe 173into the cylinder chamber 172 to move the piston 166 together with thesleeve 137 and spindle 141 toward the right into a loading position tofacilitate a loading operation. When the solenoid S2 is energized, thevalve member 176 is moved toward the right so that fluid under pressureis passed from the valve chamber 178, through the pipe 176 into thecylinder chamber 171 to move the piston 166 together with the sleeve 137and spindle 141 toward the left into a piston for a grinding operationwith the work shoes 135 and 136 supporting a work piece to be ground.

A work loading and discharging' mechanism is provided automatically toconvey work pieces to be ground to and from a grinding position. Aplurality of work pieces 185 are loaded into a work chute 186 (Fig. 7).An escapement lever 187 is provided for controlling the intermittentlysuccessive Work pieces to roll into a turret to be hereinafterdescribed. The lever 187 is provided with an arm 188 which is normallyheld in a broken line position 188a to retain a Work piece 15b in'theend portion of the chute 186. The lever 187 is pivotally supportedby astud 189. A stop stud 19 0, is provided to limit the swinging movementof the lever.187 in a counter clockwise direc tion. A tension spring 191is provided normallytojhold an arm 192 of the escap ement lever187 inabroken line position 192a. The lower end of the lever 187' is providedwith an actuating roller 193 which is arranged to be engagedsuccessively by a plurality of cam surfaces 194 formed on the peripheryof a' rotatable turret wheel 195. The turret wheel 195 is fixedly keyedonto the left hand end of the rotatable shaft 196 ('Fig. 3) which isjournaled in spaced bearings 200 and 201 supported by a housing 199which is clamped onto the swivel table 14 (Fig. 7). The turret wheel 195is provided with a plurality of symmetrically arranged work apertures197, 197a, 197b, 197e, 197a,

and 197s which are arranged to receive successive work pieces 185 fromthe loading chute 186 and to convey them into a' grinding position andthereafter to discharge ground Work pieces into a discharge chute 198.

As the turret wheel 195 is intermittently indexed, a cam face 194 formedon the periphery of the turret wheel 195 engaged the actuating roller193'to swing escapement lever 187 in a clockwise direction so as toallow the work piece 185b to roll into the work aperture 197 in theturret wheel 195. The rocking of the escapement lever in a clockwisedirection raises the arm 192 into the full line position (Fig. 7) sothat it engages the work piece 185a to hold it from rolling down theloading chute 186.

An indexing mechanism is provided for intermittently indexing the turretwheel 195 after each grinding operation. This mechanism is preferably ageneva-type indexing mechanism including a geneva plate 205 which ismounted on the right hand end of the shaft 196 (Fig. 3). The genevaplate 205 is provided with a plurality of symmetrically arranged radialslots 206, 206a, 2061), 2060, 206d and 206e and is also provided with aplurality of partial cylindrical'holding surfaces 207, 207a, 207b, 207c,

' 207d, and 207s.

' An actuating arm 208 is rotatably supported by a oneway type ballclutch 209 which is in turn supported on a shaft 210. The arm 208 isprovided with a stud 211 which supports a roller 212 .(Fig. 5). When thearm 208 is revolved in a counter clockwise direction the roller 212rides into one of the radial slots 206 into a geneva plate 205. As theroller 212 rides into the slot 206 a partial cylindrical holding surface214 moves out of engagement with the holding surface 207a on the genevaplate 205. Continued movement of the arm 208 in a counter clockwisedirection moves the roller within the radial slot 2060 to impart aclockwise indexing movement to the geneva plate 205 and to the turretwheel 195.

A hydraulically operated mechanism is provided for actuating the arm 208comprising a cylinder 215 (Fig. 6) which contains a slidably mountedpiston 216. The piston 216 is connected to the left hand end of thepiston rod 217. A plurality of rackteeth 218 are formed on the pistonrod 217 which mesh with a gear 219 which is fixedly mounted on the shaft210. When it is desired to index the turret wheel 195', fluid underpressure is passed through a pipe 220 into a cylinder chamber 221 tomove the piston 216 toward the left.(Fig. 6). The movement of the piston216 toward the left continues until the piston 216 engages a stop screw222 mounted within the left hand end of the cylinder 215. During thismovement of the piston 216, fluid within a cylinder chamber 223 exhauststhrough a pipe 224. The stop screw 222 is adjusted to determine theindexing stroke of the piston 216 so that the roller 212 will impart arotary indexing movement to the geneva plate 205 Which continues'untilthe partial cylindrical surface 214 on the arm 208 rides into engagementwith the stop surface 207b.

. As the piston rod 217 approaches the left hand end of its stroke, astop screw 225 carried by the piston rod 217 engages the actuatingplunger 226 of the limit switch LS3 which functions in a manner to behereinafter described.

A control valve 230 is provided for controlling the admission to andexhaust of fluid from the [cylinder 215.

, c s The valve 230 is a piston type valve having a slidably mountedvalve member 231 having a plurality of spaced valve pistons formingspaced valvechambers 232, 233

. and 234. The valve member 231' is provided with a central passage 235which interconnectsthe valve chamber 232 with the valve'chamber 234. Acompression. spring 236 serves normally to hold the valve member 231 ina left hand end position. A solenoid S3 is provided which when energizedserves to shift thevalve member 231 in a reverse position to pass fluidthrough the pipe 220 to initiate an indexing movement of the work turret195.

When the solenoid S3 is energized fluid under pressure from the pipe 73enters the valve chamber 233 and 7 passes through the pipe 220 into thecylinder chamber 221 to start an indexing movement. During the index ingmovement fluid within the cylinder chamber 223 exhausts through the pipe224 into the valve chamber 232 and passes out through a throttle valve237 and exhausts through a pipe 238 into the reservoir 72. It will bereadily apparent from the foregoing disclosures that by manipulation ofthe throttle valve237, the rate of the indexing movement may be readilycontrolled;

A holding pawl 240 is arranged to engage a notch 241 formed in'thegeneva arm 208 so that the arm 208 is.

held against movement in the opposite direction during aresettingmovement of the index piston 216. During the resetting movement of thepiston 216 (Fig. 6), after an indexing'of the turret 195-hasbeencompleted, the piston 216 moves in a direction toward the right.During this movement the ball clutch 209 allows the shaft 210 to rotatewithout transferring any motion to the arm 208.

During a grinding operation, the work loading turret 195 is positionedin a left hand end position (Fig. 3) so that the turret is out ofengagement with the work piece being ground. After a work piece has beenground, theshaft 196 together with the work turret 195 are moved towardthe right (Fig. 3) before an indexing movement of the work turret 195takes place. This movement of the turret 195 toward the right isaccomplished by and in timed relation with the movement of sleeve 137.As illustrated in Fig. 3, the flange 139 is provided with a radiallyprojecting pin 245 which engages a groove 246 formed in a hub 247 whichis formed integrally with the turret 195. When the turret 195 is movedtoward the right the work piece 185 is held by the permanent magnetchuck 24 and the work shoes 136'move toward the right out of engagementwith the periphery of the work piece which has been ground so that thework piece is again supported in one of the pockets 197 in the loadingturret 195. The turret may then be indexed to present the next workpiece 185 into axial alignment with the work shoes 135 and 136 afterwhich the piston 166 moves the spindle 141 and the sleeve 137 toward theleft so that the work shoes 135 and 136 slide into supporting engagementwith the work piece 185 as the turret wheel 195 is moved toward the left(Fig. 3) out of engagement therewith. The permanent magnet chuckthengrips the work piece 185 and serves to drive the. same during thegrinding operation. The work supporting shoes 135 and 136 are beveled onthe side adjacent to the turret so that the work piece will slide intosupporting engagement therewith as the shoes are moved toward the left.The work shoes 135 and 136 are adjusted so that at the start of thegrinding operation, the axis of the work piece to be. ground is locatedslightly above the axis of rotation of the work driving spindle 23 andthe permanent magnet chuck 24. The magnetism of the work driver'24 issufficient to impart the desired rotary motion to the work piece 185during a grinding operation. The magnetism of the driver 24, however, issuch that the work piece 185 may shift laterally relative to the driver,that'is, in a di-' rection normal to its axis of rotation so thatthework piece is maintained in operative engagement with the worksupporting shoes 135 and 135.

A cycle control lever 25!? is pivotally mounted on the front of themachine base. When the lever 250 is rocked in a clockwise direction(Fig. 9) a normally open start switch SW2 is closed to start a grindingcycle. A normally closed cycle stop switch SW1 is provided which may beopened by a counter clockwise movement of the cycle control lever 250 tostop the cycle of the machine at any time desired.

Referring now to Fig. 9, the electric power is off and the electricswitches and controls are as follows:

Switches Switch SW1 is closed and serves to provide a holding circuit tomaintain relay switch CR1 closed as soon as the power is turned on.

Switch SW2 is opened. This switch is a momentary start switch whichserves when closed to energize the relay switch CR1.

Switch SW3 when closed serves to automatically recycle the machine. If amanual control is desired the switch SW3 may be left open.

Switch SW4 is opened and the hydraulic pump motor stops.

Solenoids Solenoid S1 is deenergized and the wheel slide 35 is in arearward or inoperative position with the piston 56 positioned as shownin Fig. 9. The feed piston 96 is in a reset position and the movablework shoe 136 in an uppermost or start position.

Solenoid S2 is deenergized and the work turret 195 is in a loadingposition, that is, toward the right as viewed in Fig. 3 with the workshoes 135 and 136 out of engagement with the work.

Solenoid S3 is deenergized with the turret index piston 216 in a resetposition (Fig. 9). The normally open limit switch LS1 is held closed bymovement of the flange 139 toward the right (Fig. 3). The normallyclosed contacts of limit switch LS1 are held open. Vfhen the flange 139moves toward the left (Fig. 3) the normally closed contacts close toenergize the electric timer T 1, the relay switch CR3 to that the workdrive motor 29, and to energize the solenoid S1 to start a feeding cycleof the grinding wheel 32.

The normally closed contacts of limit switch LS2 are closed. Used as aholding circuit to hold relay switch CR2 and solenoid S2 energized. Theswitch LS2 is momentarily open during the rearward movement or" thewheel slide 39 to break the holding circuit.

The limit switch LS3 is normally open. When closed by movement of theturret index piston 21d it automatically starts the cycle again providedthe switch SW3 is closed. Otherwise the cycle start lever 250 must beactuated to momentarily close the switch SW2 to start each cycle ofoperation.

The relay switch CR1 serves as a holding relay to supply power to themachine.

The time delay relay TDZ is energized by either the switch SW2 or thelimit switch LS3 and is held energized by the limit switch LS2 tomaintain the solenoid S2 energized. The relay switch CR3 is energized bythe closing of contacts RC1 of the timer T1 when the timer T1 isenergized by the closing of the normally closed contacts of the limitswitch LS1 to start the work drive motor 20.

The operation of the improved grinding machine will be readily apparentfrom the foregoing disclosure. A plurality of work pieces 185 to beground are loaded in the loading chute 1%. The switch SW4 is closed tostart the hydraulic pump 71? and to start an indexing movement of theturret 195 by energizing the solenoid S3, through the normally closedcontacts of the limit switch LS1. The cycle start lever 25$) is rockedin a clockwise direction to momentarily close the start switch SW2 so asto energize the relay switch CR1. The normally closed switch SW1 servesto set up a holding circuit to maintain the relay switch CR1 energized.The closing of contacts of the re ay switch CR1 serves to supply powerto the various mechanisms of the machine. The closing of the switch SW1also energizes the relay switch CR2 and the normally closed contacts ofthe limit switch LS2 maintains the relay switch CR2 energized. When thecontacts of relay switch CR2 close a circuit is completed to energizethe solenoid S2 which serves to move the piston 166 toward the left tomove the work shoes 135 and 136 into supporting engagement with the workpiece to be ground as the work turret 195 moves out of engagementtherewith. As the work shoes 135 and 136 move to an operative position,the normally open contacts of the limit switch LS1 open to deenergizethe solenoid S3 and the work turret index piston 216 moves toward theleft (Fig. 9) to reset the parts for the next operation. This movementserves to open the normally open contacts or" the limit switch LS3.

When the work shoes 135 and 136 are moved in an operative position, thenormally closed contacts of the limit switch LS1 close to energize thetimer T1 thereby closing the timer contacts LCl, RC1, and CCl. The timercontacts LCl serves to close a holding circuit to maintain the timer T1energized. The closing of the timer contacts RC1 serves to energize therelay switch CR3 to start the work drive motor 20 and the closing of thecontacts CCl serve to energize the solenoid S1 to start movement of thefeed piston 56 toward the left to move the grinding wheel rapidlyintogrinding engagement with the work piece to be ground.

hVhen the solenoid S1 is energized fluid under pressure is passed tomove the wheel slide piston 56 to cause a rapid approaching movement ofthe grinding wheel 32. After the sequence valve opens, fluid underpressure is passed to start movement of the feed piston 96 toward theright to start a grinding feed and at the same time fluid is passed tothe shoe actuating cylinder 156) to move the piston 151 toward the left(Fig. 9) to start a slow downward movement of the work shoe 136 duringthe grinding operation. When the timer T1 times out the contact LCl, RC1and CO1 open to deenergize the relay switch CR3 thereby stopping thework drive motor 2% and also to deenergize the solenoid S1 which shiftsthe feed control valve 61) to cause a rapid rearward movement of thepiston 56 and a rapid resetting movement of the feed piston 96 towardthe left to reset the feed wheel 51. During the rearward movement of thefeed slide 39, an adjustable collar 260 (Fig. 9) momentarily opens thelimit switch LS2 to break the holding circuit to deenergize the relayswitch CR2. The contacts of relay switch CR2 open thereby deenergizingthe solenoid S2. The deenergizing of the solenoid S2 serves in a mannerpreviously described to mOVe the work turret 195 together with the worksupporting shoes and 136 toward the right into a loading position.During this latter movement, the normally closed contacts of the limitswitch LS1 open to reset the timer T1 when the work turret 195 hascompleted its movement toward the right into its loading position. Thenormally open contacts of the limit switch LS1 close so as to energizethe solenoid S3 to move the turret index piston 216 toward the right(Fig. 9) to index the work turret 195 in'a manner previously describedto present a new work piece to be ground into a grinding position. Whenthe piston rod 217 moves toward the right to index the work turret 195,it closes the normally open limit switch LS3 to energize the relayswitch CR2 so as to energize the solenoid S2 thereby starting the nextmachine grinding cycle.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possibleembodiments may be made, of the above invention and as manychanges might be made in the embodiment of the above set forth, it is tobe understood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and in alimiting sense.

liclaim:

1. In a grinding machine having a base, a transversely movable rotatablegrinding wheel, a rotatable work spindle having a work driver to rotatea work piece during a grinding operation, a fixedly mounted worksteadying shoe to engage the periphery of a work piece at a point belowthe work axis and adjacent to the line of .contact between the grindingwheel and the work piece, a second Work steadying shoe to support thework piece diametrically opposite to the grinding wheel at a point abovea horizontal plane passing through the work axis, a feeding mechanism tofeed the grinding wheel transversely in either direction, and means toimpart an arcuate motion to said second shoe toward said fixed shoe byand in timed relation with the infeeding movement of the grinding wheel.

2. In a'grincling machine, as claimed in claim 1, in combination withthe parts and features therein specified of means to move the worksteadying shoes in a direction parallel to the axis of said spindle toand from an operative position, and means including a rotatable workloading turret automatically to position successive work pieces intooperative position relative to said chuck.

3. In a grinding machine, as claimed in claim 1, in combination with theparts and features therein specified of means to move said worksteadying shoes in a direction parallel to the axis of said spindle toand from an operative position, means includinga rotatable work loadingturret automatically to position successive work pieces into anoperative position relative to said chuck, and means including anindexing mechanism intermittently to index said turret by and in timedrelation of movement of said shoes to an inoperative position.

4. In a grinding machine as claimed in claim. 1, in combination with theparts and features therein specified of means including a piston andcylinder to move. said work steadying shoes in a direction parallel tothe axis of said spindle to and from an operative position, a rotatablework loading turret automatically to position successive work piecesinto an operative position relative to said chuck, an index mechanismforsaid turret, and means including a piston and cylinder to actuatesaid index mechanism in timed relation of movement of the work shoes toan inoperative position. a

S. In a grinding machine, as claimed in claim 11,-in combinau'on withthe parts and features therein specified of means including 'a pistonand cylinder to move said work steadying shoes in a direction parallelto the axis of said spindle to and from an operative position, a controlvalve therefor, a rotatable work loading turret automatically toposition successive work pieces int'o'a'n operative position relative tosaid chuck, an index mechanism for said turret, means including a pistonand cylinder to actuate said index mechanism, a control valve therefor,and meansactuated by and in timed relation with movement of said shoesto an inoperative position to actuate said latter valve to initiate anindexing movement of said turret.

ssssssss i2 diametrically opposite the grinding wheel at a pointslightly above a,horizontal plane passing through the work axis, afeeding mechanismjncludingja piston and cylinder to feed the grindingwheel transversely in either direction, and means. including a piston.and cylinder .op- *erativelyiconnectedto impart an arcuate motion tosaid second shoe toward. said fixed shoe by and in timed relation withthe infeeding movement of the grinding wheel.

7. In a grinding machine having a base, a transversely movable rotatablegrinding wheel, a rotatable work spindle having a plane-faced permanent,magnet work driver to rotate a Work piece during a grinding operation,means including a motor to rotate said spindle, an axially movablenon-rotatable sleeve, a fixedly mounted work steadying shoe supported onthe end of said sleeve which is arranged to engage the'periphery'surface of the work piece at a point below thework axis and adjacent tothe line of contact between the grinding wheel and the work piece, anaxially movable rotatable spindle within said sleeve, a work steadyingshoe adjustably mounted on end of said spindle which is arranged toengage the periphery of the workpiece at a point diametrically oppositethe grinding wheel above a horizontal plane passing through the workaxis, said shoes beingarranged to support the peripheral surface of awork piece during the grinding operation with its axis above the. axisof the work driving spindle, and means actuated in timed relation withthe infeeding movementof the grinding ,wheel to impart a rotary motionto said spindle to' cause a gradual arcuate movement of said second shoetoward the fixed shoe as the work is reduced in size to facilitaterounding-up the work. I J

8. Ina grinding machine, as claimed in claim 7, in combination with theparts. and features therein specified of'a gear on said spindle, arack-barmeshing therewith, and means including a piston andcylindertomove said rack-bar so as to impart a rotary motion to said gear and saidspindle to move the work shoe'supported thereby toward the fixedlymounted shoe during a grinding operation. I

9. In a grinding machine as claimed in claim 7, in combination with theparts and features therein specified of means including a piston andcylinder operatively connected to feed said grinding wheel transverselyin either direction, 'a control valve operatively connected to controlthe admission to and exhaust of fluid'from said cylinder, a gear on saidspindle, a rack-bar meshing therewith, a piston and cylinder operativelyconnected to move said rack-bar to impart a rotary motion to saidspindle so as to move the work shoe supported thereby, and op erativeconnections between said control valve and said latter cylinder to movesaid shoe relatively toward and from the fixed shoe by and in timedrelation to the feeding movement of the grinding wheel.

10. In a grinding machine as claimed in claim 7, in combination with theparts and features therein specified of means including a piston andcylinder operatively connected simultaneously to move said'work shoes toand from .an operative position to facilitate a loading and unloadingoperation.

11. in a grinding machine as claimed in claim 7, in combination with theparts and features therein specified of means including a rotatable workloading turretauto- No references cited.

